A higher than expected volume of claims for payment protection insurance compensation has forced Barclays to add an extra £300m to its £1bn provision in a move that indicates other banks might also be facing higher bills for the mis-selling of the insurance.

The bank is reporting its first quarter results the day before its annual meeting at which one in four shareholders are expected to register a protest against the bank's pay policies, particularly the £17m handed to chief executive Bob Diamond and the £5.7m the bank paid to cover his tax when he relocated from the US to become chief executive.

Stripping out that additional £2.6bn cost of paying back its own debt and the PPI charge, profits were up 22% at £2.4m.

Diamond said the environment in which the bank operated was "unpredictable" but reckoned it was able to adapt.

The terms of Diamond's bonus were tweaked last week in an effort to quell any shareholder rebellion. Half of the £2.7m awarded to him in shares for 2011 will only pay out if the bank's return on equity - a measure of shareholder performance - is higher than the cost of equity - a measure of the cost of doing business for Barclays. At the end of 2011 the ROE was 6.3% although this was 12.2% in the first quarter of 2012.

Barclays continues to make a loss in European operations, largely because of its business in Spain, although the losses narrowed by 27% to £43m.

Barclays - which is to hold a "citizenship day" next month - also provided details of its citizenship in the first quarter when it lent £10bn in the UK, raised £1.5bn under the government's national loan guarantee scheme and helped big companies raise £266m. Diamond made citizenship one his four priorities on becoming chief executive in January 2011.

In February this year, Barclays admitted that it was the bank that had been targeted by the Treasury when it closed down two tax avoidance schemes.